Shaft Seal System, Turbomachine with Shaft Seal System, and Method of Sealing a Shaft

Abstract

Described herein is a shaft seal system of a shaft supported in a bearing housing of a turbomachine. The shaft seal system includes a rotor-side seal arranged between the bearing housing and the shaft. Additionally, the shaft seal system includes an axial bearing supporting the shaft. Further, a gap is provided between a rotor-side thrust bearing surface of the axial bearing and an opposite surface of the shaft. A gap width of the gap is adjustable as a function of rotation speed of the shaft.

1 - 15 . (canceled) 
     
     
         16 . A shaft seal system of a shaft supported in a bearing housing of a turbomachine, comprising:
 a rotor-side seal arranged between the bearing housing and the shaft;   an axial bearing supporting the shaft; and   a gap provided between a rotor-side thrust bearing surface of the axial bearing and an opposite surface of the shaft, wherein a gap width of the gap is adjustable as a function of rotation speed of the shaft, wherein the gap is a lubrication inlet gap of the shaft seal system, wherein the axial bearing comprises a main thrust bearing surface facing in an opposite direction than the rotor-side thrust bearing surface, wherein the main thrust bearing surface faces a thrust ring provided around the shaft, and wherein the main thrust bearing surface has a larger surface area than the rotor-side thrust bearing surface, and wherein the axial bearing comprises one or more lubrication supply channels for bearing lubrication.   
     
     
         17 . The shaft seal system according to  claim 16 , wherein the rotor-side thrust bearing surface is an auxiliary thrust bearing surface, and wherein the opposite surface of the shaft is an annular surface extending in a radial direction of the shaft. 
     
     
         18 . The shaft seal system according to  claim 16 , wherein the shaft is movable in an axial direction with respect to the axial bearing. 
     
     
         19 . The shaft seal system according to  claim 16 , wherein the gap width of the gap is increasable with increasing rotation speed of the shaft. 
     
     
         20 . The shaft seal system according to  claim 16 , wherein the gap width of the gap is decreasable with decreasing rotation speed of the shaft. 
     
     
         21 . The shaft seal system according to  claim 16 , wherein the axial bearing comprises an integrated radial bearing. 
     
     
         22 . A turbomachine comprising a shaft seal system according to  claim 16 . 
     
     
         23 . A method for sealing a shaft supported in an axial bearing supported in a bearing housing of a turbomachine, comprising adaptively adjusting a gap width of a gap provided between a thrust bearing surface and an opposite surface of the shaft as a function of rotation speed of the shaft, wherein the gap is a lubrication inlet gap of the shaft seal system, wherein the axial bearing comprises a main thrust bearing surface facing in an opposite direction than a rotor-side thrust bearing surface, wherein the main thrust bearing surface faces a thrust ring provided around the shaft, and wherein the main thrust bearing surface has a larger surface area than the rotor-side thrust bearing surface, and wherein the axial bearing comprises one or more lubrication supply channels for bearing lubrication. 
     
     
         24 . The method according to  claim 23 , wherein adaptively adjusting the gap width comprises axially moving the opposite surface of the shaft relative to the thrust bearing surface. 
     
     
         25 . The method according to  claim 23 , wherein the thrust bearing surface is provided by an axial bearing supporting the shaft, and wherein the opposite surface of the shaft is a radial annular surface provided by a radial step of the shaft. 
     
     
         26 . The method according to  claim 23 , wherein adaptively adjusting the gap width comprises increasing the gap width with increasing rotation speed of the shaft. 
     
     
         27 . The method according to  claim 23 , wherein adaptively adjusting the gap width comprises decreasing the gap width with decreasing rotation speed of the shaft. 
     
     
         28 . The method of  claim 23 , wherein adaptively adjusting the gap width comprises employing forces acting on the shaft in the axial direction of the shaft. 
     
     
         29 . The method of  claim 23 , wherein the method comprises using a shaft seal system according to  claim 16 . 
     
     
         30 . The shaft seal system according to  claim 19 , wherein the gap width of the gap is increasable with increasing rotation speed of the shaft by employing forces acting on the shaft in the positive axial direction. 
     
     
         31 . The shaft seal system according to  claim 20 , wherein the gap width of the gap is decreasable with decreasing rotation speed of the shaft by employing hydrodynamic forces acting on the shaft in the axial direction away from the rotor-side seal. 
     
     
         32 . A turbomachine according to  claim 22 , the turbomachine being an exhaust gas turbocharger comprising a radial exhaust gas turbine. 
     
     
         33 . A turbomachine according to  claim 22 , the turbomachine being a power turbine including a generator.